Looper mechanism for sewing machines



` June 4, 1935. lH, F. GRUMAN 2,003,882

LOOPER MECHANISM FOR SEWING MACHINES Original Filed Jain. 3l, 1931 2 Sheets-Sheet 1 June 4, 1935. H. F; GRUMAN LOOPER MECHANISM FOR SEWING MACHINES Original Filed Jan. 5l, 1931 2 Sheets-Sheet 2 nventor,

Patented l`lune 4, 1935 'v 'I Y v UNITED ySTATES PATENT oFFicEf LooPER MEcHANIsM Foa SEWING MACHINES f Horace F. Gruman, St. Louis, Mo., assignor to Lewis Invisible StitchfMachine Company, St. Louis,` Mo., a corporation of Maine Original application January 31, 1931, Serial No.

512,661. Divided and this application September 19, 1931', Serial4 No. 563,841

Claims. (Cl. 1158-4200) This invention relates to newand useful imarm Il)` of comparatively small cross sectional provements in looper mechanisms for use in conarea. A bracket I I is mounted within the arm I0 nection with stitch forming mechanisms of sewand extends longitudinally thereof. This bracket ing machines, and constitutesa division of my cois removably attached .to the bottom I2 of the arm' 5 pending application Serial No. 512,661, filed Jan.v by screws I3, I3 and includes spaced front and 31, 1931 for Improvements in sewing machines. rear bearings I4, I5 and an intermediate bearing Among the several objects of my invention are I6, the rear and intermediate bearings being to provide a 4-motion looper which is especially formed in a post I'I which is integral with the adapted for use in connection with a reciprocabracket II and extends upwardly into the arm tory needle having its path of travel in a sub- I0. Dowel pins I8, I8 VVwhich act as centering l0k stantially horizontal plane transverse to the line pins also connect the bottom I2 of the arm and of feed; to provide such a looper mechanism the bracket II. which is capable of application within a tubular Journaled in the bearings above described is an work arm of comparatively small cross sectional oscillatory needle shaft I9 which of course exarea; to provide driving connections between an tends longitudinally of the work arm. The Shaft oscillatory needle shaft mounted in the work arm Vis retained against longitudinal movements relaand the looper for imparting backward and fortive to the bracket I'I by means of a collar 20 ward movement to the latter; toprovide driving which engages the front bearing I4 and by the connections other than the needle shaft and exhub 2l of a needle arm 22 which is clamped tothe tending lengthwise ofthe work arm for impartshaft on the side of the bearing I6 opposite the ing needle avoiding movements to the looper, and bearing I5. The needle arm 22 extends radially to provide a ,looper mechanism which is comfrom, the shaft and thence rearwardly past the posed of comparatively few parts and is thereright hand side of the bearing post I 1, and at- -fore simple and-cheap to manufacture. f' tached to the free end of the needle arm is a With these and other objects in view which will curved needle 23 rwhich oscillates in an arcuate 25 more fully appear, lthe natureyof the invention ypath extending above the shaft I9 and in a verwill be more clearly understood by following the tical plane at right angles to the longitudinal description, the appended claims, and the sevaxis of said shaft. .Thus the needle 23 oscillates eral views illustratedin the-accompanying drawwhollyy within the coniines' of the cross sectional ingS- area of the work arm II).Y f.

In the drawngs:- Y y l Cooperatingiwith the needle 23 to form a line Figure 1 is a top plan view of a work arm of Grover and Baker stitches is a 4-motion showing the application of my invention therein, threaded looper 24 which is rigidly connected,

Figure 2 is a detail verticalsectional view preferably integrally, to a looper holder 25 havshowing vtliebearings for the needle shaft `and ing beveled side edges 26, 26. `A loopercarrier 35 one gear connection between the shaft and the 21 is mounted for oscillatory movements in a looper, c recessed bearing 28 formed in the post Il, the Figure 3 is a perspective view of a bracket on longitudinal axis of the bearing 28 being in a which the looper mechanism is mounted, f Vhorizontal plane and in a plane at right angles 40 Figure 4 is a perspective view of the looper to the longitudinal axis Vof the needle shaft I9, 40 carrier, and the bearing being located on one side of said Figure 5 is a perspective View of the looper` and shaft. It will also be noted that the longitudinal the looper holder, axis of the bearing 28 is in the vertical plane con- Figure 6 is a perspective view of the guard plate taining the path of travel of the needle 23. The

which retains the looper carrier in itsbearing, looper carrier 27 is provided on its outer face with 45 Figure 7 is a detail horizontal sectional view a radially extending groove or guiding channel showing the means for oscillating the looper car- 29 in Which the 1001361 hOldeI 25 iS mOunted foi' rier from the needle shaft, and y straight line reciprocatory movements. 'The Figure 8 is a detail elevation of a modiiied form looper 24 is disposed above the'holder 25 and above y of looper avoiding mechanism. the carrier 21 and has its loop taking movement 50 Like reference numerals designate correspondtoward the operator or in other words, in a diing parts throughout the several iigures of the rection opposite the free end of the work arm. drawings. When the carrier -21 is oscillated the looper 24 is In the accompanying drawings, Ihave disclosed given its loop taking and loop shedding movemy invention as mounted within a tubular work ments or in other words its forward and back- 55 Ward travel, and when the looper holder 25 is reciprocated in said carrier the looper is given its needle avoiding movements which, as is well known in the art, is necessary to insure the iiat setting of the looper thread in the stitches being formed. A guard plate 3i! which is removably attached Ato one face of the bearing posty i1 projects slightly beyond the bearing 28 to retain the looper carrier 21 in said bearing.

In order to .oscillate the looper carrier 21 andA thereby impart loop entering and loop sheddingY movements to the looper 24, I have xedly mounted a driving bevel gear 31' on theA rear endof the needle shaft l5 and have protected saidv gear.v

from lint and the like by locating said gear in a recess 32 formed in the bearing. postv l1.

needle shaft I9. The gear coupling 31, 33V is a vl-to-l couplingv andV consequently the looper nalh/ Within the work arm i8 on the left side of the needle shaft I9, and is fulcrurned intermediate its ends on a horizontal pivot screw 3S mounted on the bracket H. The rear end of the lever 35 is provided with an upstanding arm 31 having substantially horizontalY arms 38, 39 .andforming therebetween a slot 40. `block 4I is iulcrumedy on a pivot screw 42' iixed A Sli de to the loper holder 25, and this block 4| is mounted in the slot 40' for sliding movements relative to the arms 38, 39. Thus when the vertical. link 34 is oscillated lengthwise, the lever 35 will be correspondingly oscillated, and therefore the looper holder 25 will be raised and lowered along the groove or guiding; channel 2S of the looper carrier 21` and thereby imparting needle Aavoiding movements to the looper. rThe parts are timed so that the needle avoiding movements of the looper will be imparted at opposite ends of the looper travel. The looper in its forward or loop taking movement passes under the needle and in its backward or loop shedding movement passes over the needle. f

In thev modified construction shown in Figure 8, there is shown a dependingv rock arm 43 which is rigidly connected to the rock shaft 44 and pivotally connected tol the lower end of this rock arm is a rearwardly extending link 45, one end thereof being pivotally connected to the vertical arm 46 of the bell crank lever 41 which is ulcrumed as at 48 to the post I1. The horizontal arm 49 of the bell crank lever is forked for engagement with a slide block 50 fixed to the looper holder 25, Thus upon oscillation of the rock arm 43 the looper holder 25 will be reciprocated vertically for its needle avoiding movements.

It is of course to be understood that the details of structure and arrangements of parts may be The gear 3| is in constant mesh ywith a driven gear 33 fixed to the inner face of the looper carrierv 21 to oscillate the latter upon oscillation of they variously changed and modified without departing from the spirit and scope of my invention.

I claim:

1. In a sewing machine, the combination with anroscillatory shaft; of afl-motion looper; and means for operating said looper comprising a looper carrier supported for oscillation about an axis disposed at right angles to the longitudinal axis of the shaft, a looper holder mounted in the carrier dfor 'bodilyA movements therewith and for yradial reciprooatory movements relative thereto,

driving connections between the shaft and the carrier for imparting loop-taking and loopshedding movements to the looper, and means separate from the shaft for imparting needleavoiding. movements to the looper.

.2. In a sewing. machine, the combination with an oscillatory shaft; of a 4-motion looper; and means for operating said looper comprising a xed casing having a circular bearing, a looper' carrier mounted' in the bearingof the casing for oscillations about an axis disposed at right angles to the longitudinal axis of the shaft, a looper holder mounted in the carrier for bodv-ily movements therewith and for radial reciprof catory movements relative thereto, driving connections between the shaft andf the carrier for imparting loop-taking and loop-shedding movements to the looper. andE means separate from they shaft for imparting needle-avoiding movements to the looper.v

3.v In a sewing machine, the combination with an oscillatory shaft; of a *l-motion looper; and means for operating said looper comprising a fixed casing having a circular bearing, a looper carrier mounted' inA the bearing of the casing for oscillations about' an axis disposed at right angles to the longitudinal axis of the shaft, a looper holder mounted in the carrier for bodily movements therewith and for radial reciprocatory movements relative thereto, driving connections between the shaft and the carrier for imparting loop-taking,A and l'oopashedding movements to the looper comprising a driving gear 'iixed to the shaft and a driven gear fixed to the f carrier, and meansr separate from the shaft for imparting kneedle-avoiding movements to the looper.

4. Inr a stitch form-ing mechanism, the combination of a 4-motion threaded looper, and means for operating said looper comprising' an oscillato-ry carrier, a looper holder mounted in the carrier for bodily movements therewith and for `radial reciprocatory movements relative thereto, and separate means for oscillating the carrier and for reciprocating the holder.

5. In a stitch forming mechanism, the combination of a, 4-motion threaded looper, and means for operating said looper comprising a fixed casing having a circular bearing, a looper carrier mounted in the bearing of the casing foroscillations about an axis parallel with the lplane of needle reciprocations, said carrier being provided with a radially extending guiding channel, a looper holder mounted in said guiding channel for bodily movements with the carrier and for radial reciprocatory movements relative thereto, and separate means for oscillating the carrier and for reciprocating the holder.

HORACE F. GRUMAN. 

